1. Field of the Invention
This invention relates generally to pressure sensing devices and, more particularly, to pressure sensing devices employing force transducer ink.
2. Discussion of the Related Art
Recently, a force transducer ink has been developed that, upon the application of pressure to a layer of the material, results in a dramatic change in resistance of the layer. This material has been utilized in a variety of configurations for detecting the application of pressure. In particular, a typical pressure sensing device 10 is shown in FIG. 1. This device includes a first conducting pattern 11 and a second conducting pattern 12 deposited on an insulating material 2. The conducting patterns are separated so that a very large resistance, essentially an open circuit value, is measured between terminals coupled to the two patterns. On a second sheet of insulating material 3, a conducting pattern 14 is deposited and a layer of the force transducer ink is then applied over the conducting pattern. The two insulating materials are then positioned in so that the pressure sensing ink 13 separates the conducting patterns 11 and 12 from the conducting pattern 14. When a pressure is applied to this configuration, a path is formed from the conducting pattern 11 through the force transducer ink 13 to the conducting region 14 and then back through the force transducer ink to the second conducting pattern 12. Thus, application of a force to the configuration can be measured by a change in resistance as measured by a change in resistance as measured between conducting pattern 11 and conducting pattern 12.
Although this pressure sensing configuration can detect application of pressure, a need has been felt for a pressure sensing device that, in addition to determining the presences of a pressure, can provide a quantitive measure of the pressure applied to the configuration.